JP4926776B2 - Vehicle driving force control device - Google Patents

Description

  The present invention relates to a driving force control device for a vehicle that controls driving force so as to appropriately maintain a grip force of a wheel in various running scenes of starting, going straight, and turning.

  Conventionally, various traction control devices that restrict and control the driving force to suppress wheel slip have been proposed and put into practical use.

For example, in Japanese Patent Laid-Open No. 5-214974, the slip ratio of the drive wheel is calculated based on the drive wheel speed and the vehicle body speed, and when the slip ratio exceeds a predetermined threshold, the engine output torque is reduced to reduce the drive wheel speed. A technique for feedback-controlling a throttle valve in order to suppress excessive slip has been disclosed.
Japanese Patent Laid-Open No. 5-214974

  By the way, at the time of cornering of the vehicle, the lateral force acting on the tire is increased, and the front / rear driving force and the slip ratio which are allowable for maintaining stable vehicle behavior are reduced. For this reason, in the traction control device as disclosed in Patent Document 1 described above, a minute tire necessary for stabilizing the vehicle behavior during cornering from the limit of calculation accuracy when estimating the ground speed of the vehicle body Since it becomes difficult to detect slip, there is a problem that it is difficult to suppress the driving force by accurately obtaining the torque down amount in order to maintain the stability of the vehicle.

  The present invention has been made in view of the above circumstances, and it is possible to improve the stability of a vehicle by accurately controlling the driving force accurately and accurately in every traveling scene such as starting and straight traveling as well as cornering. An object is to provide a driving force control device.

The present invention relates to a first control amount calculation means for estimating a friction circle limit of a road surface and calculating a control amount of a driving force for torque reduction based on the friction circle limit as a first control amount, and at least a slip ratio of a wheel. And a second control amount calculating means for calculating a control amount of the driving force for torque reduction as a second control amount, and correcting the driving force according to the first control amount and the second control amount. Rutotomoni and a driving force correction means for, the first control amount calculating means, the first tire force estimation unit that estimates a tire force generated in the wheel on the basis of the driver request as a first tire force, wheel A second tire force estimating unit that estimates the currently generated tire force as a second tire force, a friction circle limit value setting unit that sets a friction circle limit value of the tire force, and the first tire force And the above friction circle limit value The first over-tyre force estimation unit that estimates a tire force that exceeds the frictional circle limit value as a first overtire force, and the frictional circle limit value is exceeded based on the second tire force and the frictional circle limit value. A second over-tyre force estimating unit that estimates a tire force as a second over-tyre force; and a first control amount that sets the first control amount based on the first over-tyre force and the second over-tyre force. 1 control amount setting unit .

  According to the vehicle driving force control device of the present invention, it is possible to improve the stability of the vehicle by accurately and accurately controlling the driving force not only during cornering but also in every traveling scene such as starting and straight traveling. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 14 show an embodiment of the present invention, FIG. 1 is a functional block diagram showing the configuration of a driving force control device, FIG. 2 is a flowchart of a driving force control program, and FIG. 3 is a first traction control unit. FIG. 4 is a flowchart of the first control amount calculation program, FIG. 5 is a flowchart continuing from FIG. 4, and FIG. 6 is an example of engine torque set by the engine speed and throttle opening. FIG. 7 is an explanatory diagram showing an example of the relationship between the accelerator opening and the throttle opening for generating the required engine torque, FIG. 8 is a flowchart of an additional yaw moment calculation routine, and FIG. 9 is a lateral acceleration saturation coefficient FIG. 10 is a characteristic map of the vehicle speed sensitive gain, FIG. 11 is an explanatory diagram of the difference in the value of the additional yaw moment between the high μ road and the low μ road, and FIG. FIG. 13 is a functional block diagram showing the configuration of the second traction control unit, and FIG. 14 is a flowchart of the second control amount calculation program. In this embodiment, a four-wheel drive vehicle with a center differential is taken as an example of the vehicle, and a vehicle in which the longitudinal driving force distribution can be varied from the base torque distribution Rf_cd by the center differential by a differential limiting clutch or the like (fastening torque TLSD). Explained as an example.

In FIG. 1, reference numeral 1 denotes a vehicle driving force control device that is mounted on a vehicle and appropriately suppresses the driving force. The driving force control device 1 includes a throttle opening sensor 11, an engine speed sensor 12, an accelerator. An opening sensor 13, a transmission control unit 14, a lateral acceleration sensor 15, a yaw rate sensor 16, a steering wheel angle sensor 17, a wheel speed sensor 18 for each wheel, a longitudinal acceleration sensor 19, and a road surface μ estimation device 20 are connected, and a throttle opening θth. , Engine speed Ne, accelerator opening θACC, main transmission gear ratio i, torque converter turbine speed Nt, differential limiting clutch engagement torque TLSD, lateral acceleration (d ² y / dt ² ), yaw rate γ, steering wheel angle θH, wheel speed of each wheel ωfl, ωfr, ωrl, ωrr (subscript “fl” is the left front wheel, “fr” is the right front wheel, “rl” is the left rear wheel, “rr” Showing the right rear wheel), the longitudinal acceleration ^{(d 2 x / dt 2)} , the road surface friction coefficient μ is inputted.

  Based on these input signals, the driving force control device 1 calculates an appropriate driving force in accordance with a driving force control program described later, and outputs it to the engine control unit 5. The engine control unit 5 outputs a control signal to a throttle control unit (not shown) to drive the motor and operate the throttle valve.

  As shown in FIG. 1, the driving force control device 1 mainly includes a first traction control unit 2, a second traction control unit 3, and a control amount setting unit 4.

The first traction control unit 2 is provided as a first control amount calculation means. The first traction control unit 2 includes a throttle opening sensor 11, an engine speed sensor 12, an accelerator opening sensor. 13, a transmission control unit 14, a lateral acceleration sensor 15, a yaw rate sensor 16, a handle angle sensor 17, a wheel speed sensor 18 for each wheel, and a road surface μ estimation device 20 are connected, and a throttle opening θth, an engine speed Ne, an accelerator opening Degree θACC, main transmission gear ratio i, torque converter turbine rotational speed Nt, differential limiting clutch engagement torque TLSD, lateral acceleration (d ² y / dt ² ), yaw rate γ, steering wheel angle θH, wheel speed ωfl of each wheel , Ωfr, ωrl, ωrr (subscript “fl” indicates left front wheel, “fr” indicates right front wheel, “rl” indicates left rear wheel, “rr” indicates right rear wheel), road surface Friction coefficient μ is input.

  As shown in FIG. 3, the first traction control unit 2 includes an engine torque calculation unit 2a, a required engine torque calculation unit 2b, a transmission output torque calculation unit 2c, a total driving force calculation unit 2d, and a front / rear ground load calculation unit. 2e, left wheel load ratio calculation unit 2f, each wheel contact load calculation unit 2g, each wheel longitudinal force calculation unit 2h, each wheel required lateral force calculation unit 2i, each wheel lateral force calculation unit 2j, each wheel friction circle limit value calculation unit 2k, each wheel required tire resultant force calculator 2l, each wheel tire resultant force calculator 2m, each wheel required overtire resultant force calculator 2n, each wheel overtire resultant force calculator 2o, over tire force calculator 2p, overtorque calculator 2q The first control amount calculation unit 2r is mainly configured.

  The engine torque calculator 2 a receives the throttle opening θth from the throttle opening sensor 11 and the engine rotation speed Ne from the engine rotation speed sensor 12. Then, a currently set engine torque Teg is obtained by referring to a map (for example, the map shown in FIG. 6) set in advance according to engine characteristics, and is output to the transmission output torque calculation unit 2c. The engine torque Teg may be read from the engine control unit 5 and used.

  The requested engine torque calculator 2 b receives the accelerator opening θACC from the accelerator opening sensor 13. Then, a throttle opening θth is obtained from a preset map (for example, a map of θACC-θth relationship as shown in FIG. 7), and based on the throttle opening θth, the map shown in FIG. 6 is used. The engine torque Teg is obtained, and this engine torque Teg is output as the requested engine torque Tdrv to the first control amount calculator 2r. The required engine torque Tdrv may be obtained from a map corresponding to the accelerator opening θACC set in advance, or may be read from the engine control unit 5 and used.

  The transmission output torque calculator 2c receives the engine speed Ne from the engine speed sensor 12, the main transmission gear ratio i from the transmission controller 14, and the turbine speed Nt of the torque converter, and the engine torque from the engine torque calculator 2a. Teg is input.

Then, for example, the transmission output torque Tt is calculated by the following equation (1), and is output to the total driving force calculation unit 2d and the wheel front / rear force calculation unit 2h.
Tt = Teg · t · i (1)
Here, t is a torque ratio of the torque converter, and is obtained by referring to a preset map of the rotational speed ratio e (= Nt / Ne) of the torque converter and the torque ratio of the torque converter.

  The total driving force calculation unit 2d receives the transmission output torque Tt from the transmission output torque calculation unit 2c.

Then, for example, the total driving force Fx is calculated by the following equation (2), and is output to the front / rear ground load calculation unit 2e and the front / rear wheel force calculation unit 2h.
Fx = Tt · η · if / Rt (2)
Here, η is drive system transmission efficiency, if is the final gear ratio, and Rt is the tire radius.

The front / rear ground load calculation unit 2e receives the total driving force Fx from the total driving force calculation unit 2d. Then, the front wheel ground load Fzf is calculated by the following equation (3) and output to each wheel ground load calculation unit 2g and each wheel longitudinal force calculation unit 2h, and the rear wheel ground load Fzr is calculated by the following equation (4). Calculate and output to each wheel ground load calculation unit 2g.
Fzf = Wf − ((m · (d ² x / dt ² ) · h) / L) (3)
Fzr = W−Fzf (4)
Here, Wf is the front wheel static load, m is the vehicle mass, (d ² x / dt ² ) is the longitudinal acceleration (= Fx / m), h is the height of the center of gravity, L is the wheel base, and W is the vehicle weight (= m G: G is the acceleration of gravity).

Lateral acceleration (d ² y / dt ² ) is input from the lateral acceleration sensor 15 to the left wheel load ratio calculation unit 2 f. Then, the left wheel load ratio WR_l is calculated by the following equation (5), and is output to each wheel ground load calculating unit 2g, each wheel required lateral force calculating unit 2i, and each wheel lateral force calculating unit 2j.
WR — 1 = 0.5 − ((d ² y / dt ² ) / G) · (h / Ltred) (5)
Here, Ltred is the average tread value of the front and rear wheels.

Each wheel ground load calculation unit 2g receives the front wheel ground load Fzf and the rear wheel ground load Fzr from the front and rear ground load calculation unit 2e, and the left wheel load ratio WR_l from the left wheel load ratio calculation unit 2f. Then, the left front wheel ground load Fzf_l, the right front wheel ground load Fzf_r, the left rear wheel ground load Fzr_l, and the right rear wheel ground load Fzr_r are calculated by the following equations (6), (7), (8), and (9), respectively. And output to each wheel friction circle limit value calculation unit 2k.
Fzf_l = Fzf · WR_l (6)
Fzf_r = Fzf · (1−WR_l) (7)
Fzr_l = Fzr · WR_l (8)
Fzr_r = Fzr · (1−WR_l) (9)

  Each wheel longitudinal force calculation unit 2h receives the engagement torque TLSD of the differential limiting clutch in the center differential from the transmission control unit 14, receives the transmission output torque Tt from the transmission output torque calculation unit 2c, and outputs the total driving force calculation unit 2d. The total driving force Fx is input from the front and the front wheel ground load Fzf is input from the front / rear ground load calculation unit 2e. Then, for example, according to the procedure described later, the left front wheel front / rear force Fxf_l, the right front wheel front / rear force Fxf_r, the left rear wheel front / rear force Fxr_l, and the right rear wheel front / rear force Fxr_r are calculated. It outputs to the wheel tire resultant force calculation part 2m.

  Hereinafter, an example of a procedure for calculating the left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right rear wheel longitudinal force Fxr_r will be described.

First, the front wheel load distribution ratio WR_f is calculated by the following equation (10).
WR_f = Fzf / W (10)
Next, the minimum front wheel torque Tfmin and the maximum front wheel torque Tfmax are calculated by the following equations (11) and (12).
Tfmin = Tt · Rf_cd−TLSD (≧ 0) (11)
Tfmax = Tt · Rf_cd + TLSD (≧ 0) (12)

Next, the minimum front wheel longitudinal force Fxfmin and the maximum front wheel longitudinal force Fxfmax are calculated by the following equations (13) and (14).
Fxfmin = Tfmin · η · if / Rt (13)
Fxfmax = Tfmax · η · if / Rt (14)

Then, the state is determined as follows.
When WR_f ≦ Fxfmin / Fx, it is assumed that the differential limiting torque is increased on the rear wheel side, and the determination value I = 1.
When WR_f ≧ Fxfmax / Fx, it is assumed that the differential limiting torque is increased on the front wheel side, and the determination value I = 3.
In cases other than the above, it is determined as normal time, and the determination value I = 2.

Next, according to the determination value I described above, the front wheel longitudinal force Fxf is calculated as follows.
When I = 1 Fxf = Tfmin · η · if / Rt (15)
When I = 2 ... Fxf = Fx.WR_f (16)
When I = 3 Fxf = Fxfmax · η · if / Rt (17)

  Then, the rear wheel longitudinal force Fxr is calculated by the following equation (18) from the front wheel longitudinal force Fxf calculated by the equation (15), (16) or (17).

            Fxr = Fx−Fxf (18)

By using the front wheel longitudinal force Fxf and the rear wheel longitudinal force Fxr, the left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right according to the following equations (19) to (22) The rear wheel longitudinal force Fxr_r is calculated.
Fxf_l = Fxf / 2 (19)
Fxf_r = Fxf_l (20)
Fxr_l = Fxr / 2 (21)
Fxr_r = Fxr_l (22)

  Note that the calculation of the front-rear force of each wheel shown in the present embodiment is merely an example, and is appropriately selected according to the drive type / drive mechanism of the vehicle.

Each wheel required lateral force calculation unit 2i has a lateral acceleration (d ² y / dt ² ) from the lateral acceleration sensor 15, a yaw rate γ from the yaw rate sensor 16, a handle angle θH from the handle angle sensor 17 (4 Wheel) The wheel speeds ωfl, ωfr, ωrl, and ωrr of each wheel are input from the wheel speed sensor 18, and the left wheel load ratio WR_l is input from the left wheel load ratio calculation unit 2f.

  Then, the additional yaw moment Mzθ is calculated according to the procedure described later (according to the flowchart shown in FIG. 8). Based on this additional yaw moment, the required front wheel lateral force Fyf_FF is calculated according to the following equation (23). ) To calculate the required rear wheel lateral force Fyr_FF. Based on these required front wheel lateral force Fyf_FF and requested rear wheel lateral force Fyr_FF, the left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right by the formulas (25) to (28) The rear wheel required lateral force Fyr_r_FF is calculated and output to each wheel required tire resultant force calculating unit 2l.

Fyf_FF = Mzθ / L (23)
Fyr_FF = (− Iz · (dγ / dt)
+ M · (d ² y / dt ² ) · Lf) / L (24)
Here, Iz is the yaw moment of inertia of the vehicle, and Lf is the distance between the front axis and the center of gravity.

Fyf_l_FF = Fyf_FF · WR_l (25)
Fyf_r_FF = Fyf_FF · (1-WR_l) (26)
Fyr_l_FF = Fyr_FF · WR_l (27)
Fyr_r_FF = Fyr_FF · (1-WR_l) (28)

Further, as shown in FIG. 8, the additional yaw moment Mzθ is first calculated in step (hereinafter abbreviated as “S”) 301 (for example, V = (ωfl + ωfr + ωrl + ωrr) / 4), and proceeds to S302. The lateral acceleration / steering wheel angle gain Gy is calculated by the following equation (29).
Gy = (1 / (1 + A · V ² )) · (V ² / L) · (1 / n) (29)
Here, A is a stability factor, and n is a steering gear ratio.

Next, the process proceeds to S303, and a map set in advance according to the value obtained by multiplying the lateral acceleration / handle angle gain Gy and the handle angle θH (Gy · θH) and the lateral acceleration (d ² y / dt ² ) is referred to. Then, the lateral acceleration saturation coefficient Kμ is calculated. As shown in FIG. 9A, the map for obtaining the lateral acceleration saturation coefficient Kμ is obtained by multiplying the lateral acceleration / handle angle gain Gy by the handle angle θH (Gy · θH) and the lateral acceleration (d ² y / dt ² ), and is set to a smaller value as the lateral acceleration (d ² y / dt ² ) increases when the handle angle θH is equal to or greater than a predetermined value. This lateral acceleration as is a high μ road when Gy · .theta.H large ^(d 2 y / dt ²⁾ is larger, the lateral acceleration ^(d 2 y / dt ²⁾ is less likely to occur in the low μ road It expresses. As a result, the value of the reference lateral acceleration (d ² yr / dt ² ), which will be described later, is large when Gy · θH is large, as shown in FIG. 9B, the lateral acceleration (d ² y / dt ² ) is large and high μ. When the road is considered to be a road, the value is set to a low value so that the correction amount for the additional yaw moment Mzθ is small.

Next, in S304, the lateral acceleration deviation sensitive gain Ky is calculated by the following equation (30).
Ky = Kθ / Gy (30)
Here, Kθ is a steering angle sensitive gain, and is calculated by the following equation (31).
Kθ = (Lf · Kf) / n (31)
Kf is the equivalent cornering power of the front shaft.

That is, according to the above equation (30), the lateral acceleration deviation sensitive gain Ky is set as a guideline (maximum value) in a state where the rudder does not work at all on an extremely low μ road (γ = 0, (d ² y / dt ² ) = 0) and the case where the additional yaw moment Mzθ (steady value) is 0 is considered.

Next, proceeding to S305, the reference lateral acceleration (d ² yr / dt ² ) is calculated by the following equation (32).

(D ² yr / dt ² ) = Kμ · Gy · (1 / (1 + Ty · s)) · θH (32)
Here, s is a differential operator, Ty is a first-order lag time constant of lateral acceleration, and this first-order lag time constant Ty is calculated by, for example, the following equation (33), where Kr is the equivalent cornering power of the rear axis. Is done.
Ty = Iz / (L · Kr) (33)

Next, in S306, the lateral acceleration deviation (d ² ye / dt ² ) is calculated by the following equation (34).
(D ² ye / dt ² ) = (d ² y / dt ² ) − (d ² yr / dt ² ) (34)

In step S307, the yaw rate / handle angle gain Gγ is calculated by the following equation (35).
Gγ = (1 / (1 + A · V ² )) · (V / L) · (1 / n) (35)

Next, the process proceeds to S308, and the following equation (36) is used, for example, considering the case where the additional yaw moment Mzθ (steady value) becomes 0 during grip travel ((d ² ye / dt ² ) = 0), The gain Kγ is calculated.

    Kγ = Kθ / Gγ (36)

  In step S309, a vehicle speed sensitive gain Kv is calculated from a preset map. This map is set in order to avoid an unnecessary additional yaw moment Mzθ in a low speed region, for example, as shown in FIG. In FIG. 10, Vc1 is 40 km / h, for example.

In S310, the additional yaw moment Mzθ is calculated by the following equation (37).
Mzθ = Kv · (−Kγ · γ + Ky · (d ² ye / dt ² ) + Kθ · θH) (37)

That is, as shown in the equation (37), the term −Kγ · γ is a yaw moment that is sensitive to the yaw rate γ, the term Kθ · θH is a yaw moment that is sensitive to the handle angle θH, and Ky · (d ² ye / dt The term ² ) is the correction value for the yaw moment. For this reason, as shown in FIG. 11, when the lateral acceleration (d ² y / dt ² ) is operated on a high μ road, the additional yaw moment Mzθ also becomes a large value, and the motion performance is improved. On the other hand, when traveling on a low μ road, the additional yaw moment Mzθ reduces the additional yaw moment Mzθ by the above-described correction value, so that the turning performance does not increase and stable traveling performance can be obtained. It has become.

Each wheel lateral force calculation unit 2j receives lateral acceleration (d ² y / dt ² ) from lateral acceleration sensor 15, yaw rate γ from yaw rate sensor 16, and left wheel load ratio WR_l from left wheel load ratio calculation unit 2f. Then, the front wheel lateral force Fyf_FB is calculated by the following equation (38), and the rear wheel lateral force Fyr_FB is calculated by the following equation (39). Based on these front wheel lateral force Fyf_FB and rear wheel lateral force Fyr_FB, the left front wheel lateral force Fyf_l_FB, the right front wheel lateral force Fyf_r_FB, the left rear wheel lateral force Fyr_l_FB, the right rear wheel lateral force Fyr_r_FB Is output to each wheel tire resultant force calculation unit 2m.
Fyf_FB = (Iz · (dγ / dt)
+ M · (d ² y / dt ² ) · Lr) / L (38)
Fyr_FB = (− Iz · (dγ / dt)
+ M · (d ² y / dt ² ) · Lf) / L (39)
Here, Lr is the distance between the rear axis and the center of gravity.
Fyf_l_FB = Fyf_FB · WR_l (40)
Fyf_r_FB = Fyf_FB · (1-WR_l) (41)
Fyr_l_FB = Fyr_FB · WR_l (42)
Fyr_r_FB = Fyr_FB · (1-WR_l) (43)

  Each wheel friction circle limit value calculation unit 2k receives a road surface friction coefficient μ from the road surface μ estimation device 20, and each wheel ground load calculation unit 2g receives a left front wheel ground load Fzf_l, a right front wheel ground load Fzf_r, and a left rear wheel ground load. Fzr_l and right rear wheel ground load Fzr_r are input.

Then, the left front wheel friction circle limit value μ_Fzfl, the right front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle limit value μ_Fzrl, and the right rear wheel friction circle limit value μ_Fzrr are calculated by the following equations (44) to (47). , Output to each wheel required over-tyre force calculating unit 2n and each wheel over-tyre force calculating unit 2o. That is, each wheel friction circle limit value calculation unit 2k is provided as a friction circle limit value setting unit.
μ_Fzfl = μ · Fzf_l (44)
μ_Fzfr = μ · Fzf_r (45)
μ_Fzrl = μ · Fzr_l (46)
μ_Fzrr = μ · Fzr_r (47)

Each wheel required tire resultant force calculation unit 2l receives the left front wheel front / rear force Fxf_l, right front wheel front / rear force Fxf_r, left rear wheel front / rear force Fxr_l, and right rear wheel front / rear force Fxr_r from each wheel front / rear force calculation unit 2h. A left front wheel required lateral force Fyf_l_FF, a right front wheel required lateral force Fyf_r_FF, a left rear wheel required lateral force Fyr_l_FF, and a right rear wheel required lateral force Fyr_r_FF are input from the lateral force calculation unit 2i. Then, the left front wheel required tire resultant force F_fl_FF, the right front wheel required tire resultant force F_fr_FF, the left rear wheel required tire resultant force F_rl_FF, and the right rear wheel required tire resultant force F_rr_FF are calculated according to the following equations (48) to (51). It outputs to the overtire force calculation part 2n. That is, each wheel required tire resultant force calculation unit 21 is provided as a first tire force estimation unit.
F_fl_FF = (Fxf_l ² + Fyf_l_FF ² ) ^1/2 (48)
F_fr_FF = (Fxf_r ² + Fyf_r_FF ² ) ^1/2 (49)
F_rl_FF = (Fxr_l ² + Fyr_l_FF ² ) ^1/2 (50)
F_rr_FF = (Fxr_r ² + Fyr_r_FF ² ) ^1/2 (51)

Each wheel tire resultant force calculation unit 2m receives the left front wheel front / rear force Fxf_l, right front wheel front / rear force Fxf_r, left rear wheel front / rear force Fxr_l, and right rear wheel front / rear force Fxr_r from each wheel front / rear force calculation unit 2h. A left front wheel lateral force Fyf_l_FB, a right front wheel lateral force Fyf_r_FB, a left rear wheel lateral force Fyr_l_FB, and a right rear wheel lateral force Fyr_r_FB are input from the calculation unit 2j. Then, the left front wheel tire resultant force F_fl_FB, the right front wheel tire resultant force F_fr_FB, the left rear wheel tire resultant force F_rl_FB, and the right rear wheel tire resultant force F_rr_FB are calculated by the following equations (52) to (55), Output to 2o. That is, each wheel tire resultant force calculation unit 1m is provided as a second tire force estimation unit.
F_fl_FB = (Fxf_l ² + Fyf_l_FB ² ) ^1/2 (52)
F_fr_FB = (Fxf_r ² + Fyf_r_FB ² ) ^1/2 (53)
F_rl_FB = (Fxr_l ² + Fyr_l_FB ² ) ^1/2 (54)
F_rr_FB = (Fxr_r ² + Fyr_r_FB ² ) ^1/2 (55)

Each wheel required over-tyre force calculation unit 2n receives from each wheel friction circle limit value calculation unit 2k, left front wheel friction circle limit value μ_Fzfl, right front wheel friction circle limit value μ_Fzfr, left rear wheel friction circle limit value μ_Fzrl, right rear wheel friction A circle limit value μ_Fzrr is input, and a left front wheel required tire resultant force F_fl_FF, a right front wheel required tire resultant force F_fr_FF, a left rear wheel required tire resultant force F_rl_FF, and a right rear wheel required tire resultant force F_rr_FF are input from each wheel required tire resultant force calculation unit 2l. . Then, the front left wheel required overtire force ΔF_fl_FF, the right front wheel required overtire force ΔF_fr_FF, the left rear wheel required overtire force ΔF_rl_FF, and the right rear wheel required overtire force ΔF_rr_FF are calculated by the following equations (56) to (59). And output to the over-tyre force calculation unit 2p. That is, each wheel required overtire force calculation unit 2n is provided as a first overtire force estimation unit.
ΔF_fl_FF = F_fl_FF−μ_Fzfl (56)
ΔF_fr_FF = F_fr_FF−μ_Fzfr (57)
ΔF_rl_FF = F_rl_FF−μ_Fzrl (58)
ΔF_rr_FF = F_rr_FF−μ_Fzrr (59)

Each wheel over-tyre force calculation unit 2o receives the left front wheel friction circle limit value μ_Fzfl, the left front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle limit value μ_Fzrl, and the right rear wheel friction circle from each wheel friction circle limit value calculation unit 2k. The limit value μ_Fzrr is input, and the left front wheel tire combined force F_fl_FB, the right front wheel tire combined force F_fr_FB, the left rear wheel tire combined force F_rl_FB, and the right rear wheel tire combined force F_rr_FB are input from each wheel tire combined force calculation unit 2m. Then, according to the following equations (60) to (63), the left front wheel over-tyre force ΔF_fl_FB, the right front wheel over-tyre force ΔF_fr_FB, the left rear wheel over-tyre force ΔF_rl_FB, and the right rear wheel over-tyre force ΔF_rr_FB are calculated. It outputs to the calculating part 2p. That is, each wheel over-tyre force calculating unit 2o is provided as a second over-tyre force estimating unit.
ΔF_fl_FB = F_fl_FB−μ_Fzfl (60)
ΔF_fr_FB = F_fr_FB−μ_Fzfr (61)
ΔF_rl_FB = F_rl_FB−μ_Fzrl (62)
ΔF_rr_FB = F_rr_FB−μ_Fzrr (63)

The over-tyre force calculation unit 2p receives the left front wheel required over-tyre force ΔF_fl_FF, the left front wheel required over-tyre force ΔF_fr_FF, the left rear wheel required over-tyre force ΔF_rl_FF, and the right rear wheel required over-tyre force from each wheel required over-tyre force calculation unit 2n. ΔF_rr_FF is input, and the left front wheel overtire force ΔF_fl_FB, the right front wheel overtire force ΔF_fr_FB, the left rear wheel overtire force ΔF_rl_FB, and the right rear wheel overtire force ΔF_rr_FB are input from each wheel overtire force calculation unit 2o. Then, the sum of each wheel required overtire force ΔF_fl_FF, ΔF_fr_FF, ΔF_rl_FF, ΔF_rr_FF and the sum of each wheel overtire force ΔF_fl_FB, ΔF_fr_FB, ΔF_rl_FB, ΔF_rr_FB are compared, and the larger value is set as the overtire force Fover. To do. That is,
Fover = MAX ((ΔF_fl_FF + ΔF_fr_FF + ΔF_rl_FF + ΔF_rr_FF)
, (ΔF_fl_FB + ΔF_fr_FB + ΔF_rl_FB + ΔF_rr_FB)) (64)

The overtorque calculation unit 2q is configured such that the engine rotation speed Ne from the engine rotation speed sensor 12, the main transmission gear ratio i from the transmission control unit 14, the turbine rotation speed Nt of the torque converter, and the overtire force Fover from the overtire force calculation unit 1p. Is entered. Then, the overtorque Tover is calculated by the following equation (65) and output to the first control amount calculation unit 2r.
Tover = Fover · Rt / t / i / η / if (65)

The first control amount calculation unit 2r receives the request engine torque Tdrv from the request engine torque calculation unit 2b, and receives the over torque Tover from the overtorque calculation unit 2q. Then, the first control amount TTCS1 is calculated according to the following equation (66) and output to the control amount setting unit 4.
TTCS1 = Tdrv-Tover (66)

  As described above, in the present embodiment, the over-tyre force calculating unit 2p, the over-torque calculating unit 2q, and the first controlled variable calculating unit 2r constitute a first controlled variable setting unit.

Next, the first control amount calculation program executed by the first traction control unit 2 will be described with reference to the flowcharts of FIGS.
First, in S201, necessary parameters, that is, throttle opening θth, engine speed Ne, accelerator opening θACC, main transmission gear ratio i, turbine speed Nt of torque converter, differential limiting clutch engagement torque TLSD, lateral acceleration ( d ² y / dt ² ), yaw rate γ, steering wheel angle θH, wheel speeds ωfl, ωfr, ωrl, ωrr and road surface friction coefficient μ of each wheel are read.

  Next, in S202, the engine torque calculation unit 2a refers to a map (for example, the map shown in FIG. 6) set in advance according to the engine characteristics to obtain the currently generated engine torque Teg.

  Next, in S203, the required engine torque calculation unit 2b obtains the throttle opening θth from a preset map (for example, the map of θACC-θth relationship as shown in FIG. 7), and this throttle opening Based on θth, the engine torque Teg is obtained from the map shown in FIG.

  Next, the process proceeds to S204, where the transmission output torque calculation unit 2c calculates the transmission output torque Tt by the above-described equation (1).

  Next, proceeding to S205, the total driving force calculation unit 2d calculates the total driving force Fx by the above-described equation (2).

  Next, the process proceeds to S206, where the front / rear ground load calculation unit 2e calculates the front wheel ground load Fzf by the above-described equation (3), and calculates the rear wheel ground load Fzr by the above-described equation (4).

  Next, proceeding to S207, the left wheel load ratio calculation unit 2f calculates the left wheel load ratio WR_l by the above-described equation (5).

  Next, the process proceeds to S208, and each wheel ground load calculating unit 2g uses the above-described formulas (6), (7), (8), and (9) to calculate the left front wheel ground load Fzf_l, the right front wheel ground load Fzf_r, and the left rear, respectively. The wheel contact load Fzr_l and the right rear wheel contact load Fzr_r are calculated.

  Next, proceeding to S209, each wheel longitudinal force calculation unit 2h uses the above-described equations (19) to (22) to calculate the left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right rear wheel. The longitudinal force Fxr_r is calculated.

  Next, the processing proceeds to S210, and each wheel required lateral force calculation unit 2i calculates the left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right according to the equations (25) to (28) described above. The rear wheel required lateral force Fyr_r_FF is calculated.

  Next, proceeding to S211, each wheel lateral force calculation unit 2j uses the above-described equations (40) to (43) to calculate the left front wheel lateral force Fyf_l_FB, the right front wheel lateral force Fyf_r_FB, the left rear wheel lateral force Fyr_l_FB, and the right rear wheel. The lateral force Fyr_r_FB is calculated.

  Next, the process proceeds to S212, where each wheel friction circle limit value calculation unit 2k calculates the left front wheel friction circle limit value μ_Fzfl, the right front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle by the equations (44) to (47) described above. The limit value μ_Fzrl and the right rear wheel friction circle limit value μ_Fzrr are calculated.

  Next, the process proceeds to S213, and each wheel required tire resultant force calculation unit 21 calculates the left front wheel required tire resultant force F_fl_FF, the right front wheel required tire resultant force F_fr_FF, and the left rear wheel required tire resultant force F_rl_FF according to the aforementioned equations (48) to (51). The right rear wheel required tire resultant force F_rr_FF is calculated.

  Next, the process proceeds to S214, and each wheel tire resultant force calculation unit 2m calculates the left front wheel tire resultant force F_fl_FB, the right front wheel tire resultant force F_fr_FB, the left rear wheel tire resultant force F_rl_FB, and the right rear wheel tire according to the equations (52) to (55) described above. The resultant force F_rr_FB is calculated.

  Next, the process proceeds to S215, and each wheel required overtire force calculation unit 2n calculates the left front wheel required overtire force ΔF_fl_FF, the right front wheel required overtire force ΔF_fr_FF, and the left rear wheel required by the above-described equations (56) to (59). The overtire force ΔF_rl_FF and the right rear wheel required overtire force ΔF_rr_FF are calculated.

  Next, the process proceeds to S216, where each wheel over-tyre force calculation unit 2o calculates the left front wheel over-tyre force ΔF_fl_FB, the right front wheel over-tyre force ΔF_fr_FB, the left rear wheel over-tyre force ΔF_rl_FB by the above-described equations (60) to (63). The right rear wheel over-tyre force ΔF_rr_FB is calculated.

  Next, the process proceeds to S217, and the over tire force calculation unit 2p calculates the over tire force Fover by the above-described equation (64).

  Next, the process proceeds to S218, where the overtorque calculation unit 2q calculates the overtorque Tover by the above-described equation (65), and the process proceeds to S219, where the first control amount calculation unit 2r performs the above-described equation (66). The first control amount TTCS1 is calculated and output to the control amount setting unit 4 to exit the program.

  As described above, according to the embodiment of the present invention, in the first traction control unit 2, the tire value generated on the wheel based on the driver request exceeds the torque circle limit value and the torque value currently generated on the wheel. The tire force is compared with the torque value that exceeds the frictional circle limit value, and the larger value is subtracted from the driving force required by the driver for correction. For this reason, not only the present but also the future excessive torque state is properly corrected, the spin and the plow are properly controlled, and the tire grip force is properly maintained to maintain the running stability of the vehicle. It is possible to improve.

  In addition, the value to be corrected by subtracting the driving force required by the driver is a torque value that causes the tire force to exceed the friction circle limit value, so the driving force in the front-rear direction is not suddenly suppressed, and the driver Therefore, there is no unnatural feeling or dissatisfaction such as insufficient acceleration (that is, the driving force is suppressed by Fxa in FIG. 12).

  In addition, the driving force in the front-rear direction may be surely suppressed to maintain the tire grip force (that is, the driving force may be suppressed by Fxb in FIG. 12). The control in this case can be realized by adding a signal line indicated by a broken line in FIG. 3 and changing the calculation in each wheel required overtire force calculation unit 2n and each wheel overtire force calculation unit 2o as follows.

  Each wheel required over-tyre force calculation unit 2n receives from each wheel friction circle limit value calculation unit 2k, left front wheel friction circle limit value μ_Fzfl, right front wheel friction circle limit value μ_Fzfr, left rear wheel friction circle limit value μ_Fzrl, right rear wheel friction The circle limit value μ_Fzrr is input, the left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right rear wheel required lateral force Fyr_r_FF are input from each wheel required lateral force calculation unit 2i. A left front wheel longitudinal force Fxf_l, a right front wheel longitudinal force Fxf_r, a left rear wheel longitudinal force Fxr_l, and a right rear wheel longitudinal force Fxr_r are input from each wheel longitudinal force calculation unit 2h.

Then, the left front wheel required overtire force ΔF_fl_FF, the right front wheel required overtire force ΔF_fr_FF, the left rear wheel required overtire force ΔF_rl_FF, and the right rear wheel required overtire force ΔF_rr_FF are calculated by the following equations (67) to (70). And output to the over-tyre force calculation unit 2p.
ΔF_fl_FF = Fxf_l− (μ_Fzfl ² −Fyf_l_FF ² ) ^1/2 (67)
ΔF_fr_FF = Fxf_r− (μ_Fzfr ² −Fyf_r_FF ² ) ^1/2 (68)
ΔF_rl_FF = Fxr_l− (μ_Fzrl ² −Fyr_l_FF ² ) ^1/2 (69)
ΔF_rr_FF = Fxr_r− (μ_Fzrr ² −Fyr_r_FF ² ) ^1/2 (70)

  Each wheel over-tyre force calculation unit 2o receives the left front wheel friction circle limit value μ_Fzfl, the left front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle limit value μ_Fzrl, and the right rear wheel friction circle from each wheel friction circle limit value calculation unit 2k. The limit value μ_Fzrr is input, and the left front wheel lateral force Fyf_l_FB, the right front wheel lateral force Fyf_r_FB, the left rear wheel lateral force Fyr_l_FB, and the right rear wheel lateral force Fyr_r_FB are input from each wheel lateral force calculating unit 2j. The left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right rear wheel longitudinal force Fxr_r are input from 2h.

Then, by calculating the left front wheel over-tyre force ΔF_fl_FB, the right front wheel over-tyre force ΔF_fr_FB, the left rear wheel over-tyre force ΔF_rl_FB, and the right rear wheel over-tyre force ΔF_rr_FB by the following equations (71) to (74), It outputs to the calculating part 2p.
ΔF_fl_FB = Fxf_l− (μ_Fzfl ² −Fyf_l_FB ² ) ^1/2 (71)
ΔF_fr_FB = Fxf_r− (μ_Fzfr ² −Fyf_r_FB ² ) ^1/2 (72)
ΔF_rl_FB = Fxr_l− (μ_Fzrl ² −Fyr_l_FB ² ) ^1/2 (73)
ΔF_rr_FB = Fxr_r− (μ_Fzrr ² −Fyr_r_FB ² ) ^1/2 (74)
On the other hand, in FIG. 1, the second traction control unit 3 is provided as a second control amount calculation means. The second traction control unit 3 includes a throttle opening sensor 11, an engine speed sensor. 12, the transmission control unit 14, the lateral acceleration sensor 15, the wheel speed sensor 18 of each wheel, and the longitudinal acceleration sensor 19 are connected, and the throttle opening θth, the engine speed Ne, the main transmission gear ratio i, the lateral acceleration (d ² y / Dt ² ), wheel speeds ωfl, ωfr, ωrl, ωrr and longitudinal acceleration (d ² x / dt ² ) of each wheel.

  As shown in FIG. 13, the second traction control unit 3 includes a vehicle speed calculation unit 3a, a slip rate calculation unit 3b, a total grip force calculation unit 3c, an engine torque calculation unit 3d, a running resistance torque calculation unit 30e, 2 control amount calculation unit 3f.

  The vehicle speed calculation unit 3a receives the wheel speeds ωfl, ωfr, ωrl, and ωrr of each wheel from the four-wheel wheel speed sensor 18, and obtains the vehicle speed V (= (ωfl + ωfr + ωrl + ωrr) / 4) by calculating the average of the wheel speeds. Calculate and output to the slip ratio calculator 3b and the running resistance torque calculator 30e.

The slip ratio calculation unit 3b receives the wheel speeds ωfl, ωfr, ωrl, and ωrr of each wheel from the four-wheel wheel speed sensor 18, and receives the vehicle speed V from the vehicle speed calculation unit 3a. Then, for each wheel, the slip ratio is calculated by the following equation (75), and the highest value is output as the slip ratio λ to the second control amount calculation unit 3f.
λ = (ω−V) / ω · 100 (75)
Here, ω is ωfl to ωrr.

The total grip force calculation unit 3 c receives lateral acceleration (d ² y / dt ² ) from the lateral acceleration sensor 15 and receives longitudinal acceleration (d ² x / dt ² ) from the longitudinal acceleration sensor 19. Then, for example, the total grip force TG corresponding to the acceleration of the vehicle body is calculated by the following equation (76) and output to the second control amount calculation unit 3f.
TG = ((K1 · (d ² x / dt ² )) ² + (K2 · (d ² y / dt ² )) ² ) ^1/2
... (76)
Here, K1 and K2 are correction coefficients.

  The engine torque calculation unit 3d is the same as the engine torque calculation unit 2a in the first traction control unit 2 described above, and the throttle opening degree θth from the throttle opening sensor 11 and the engine speed from the engine speed sensor 12 are the same. Ne is entered. Then, a currently set engine torque Teg is obtained with reference to a map (for example, the map shown in FIG. 6) set in advance according to the engine characteristics, and is output to the second control amount calculation unit 3f. The engine torque Teg may be read from the engine control unit 5 and used.

The running resistance torque calculator 30e receives the main transmission gear ratio i from the transmission controller 14 and the vehicle speed V from the vehicle speed calculator 3a. Then, a running resistance torque Tp composed of the rolling resistance of the tire and the air resistance of the vehicle body is calculated by, for example, the following expression (77) and output to the second control amount calculation unit 3f.
Tp = (K3 + K4 · V ² ) · i (77)
Here, K3 and K4 are correction coefficients.

  The second control amount calculation unit 3f includes a main transmission gear ratio i from the transmission control unit 14, a slip ratio λ from the slip rate calculation unit 3b, a total grip force TG from the total grip force calculation unit 3c, and an engine torque calculation unit. The engine torque Teg is input from 3d, and the travel resistance torque Tp is input from the travel resistance torque calculator 30e. Then, the second control amount calculation unit 3 f calculates a second control amount TTCS2 when reducing the output torque of the engine, and outputs it to the control amount setting unit 4.

Specifically, a value obtained by performing first-order lag filtering on the engine torque Teg based on the following equation (78) is calculated as the first initial engine required torque TEF.
TEF = (1−K) · TEF (k−1) + K · Teg (k) (78)

Further, the basic initial required torque Tii is retrieved from the main transmission gear ratio i and the total grip force TG based on a preset map, and the basic initial required torque Tii and the running resistance torque Tp are added. A second initial engine required torque TED is calculated.
TED = Tii + Tp (79)

  The second initial engine required torque TED is a basic initial required torque Tii that is a torque transmitted to the road surface without being consumed by excessive slip of the drive wheels, and a running resistance composed of tire rolling resistance and vehicle body air resistance. Therefore, it corresponds to a value obtained by subtracting the ineffective torque consumed by the excessive slip of the drive wheels from the current engine torque Teg.

  Then, as shown in a second control amount calculation program to be described later, when the slip ratio λ exceeds predetermined threshold values Lc1 and Lc2, the first initial engine required torque TEF and the second initial engine One of the required torques TED is selected and set as the second control amount TTCS2 and output to the control amount setting unit 4. Note that when the slip ratio λ does not exceed the aforementioned predetermined threshold values Lc1 and Lc2, torque reduction is not performed, so the second control amount TTCS2 is set to the current engine torque Teg.

  That is, the flowchart of FIG. 14 shows the second control amount calculation program. When the slip ratio λ is equal to or smaller than the first threshold value Lc1 in S401, that is, the slip ratio λ is extremely small, and the engine output torque is sufficient for the road surface. During the transmission to step S402, the routine proceeds to S402, where the second control amount TTCS2 remains at the engine torque Teg, and the torque-down control is not performed.

  Further, when the slip rate λ exceeds the first threshold value Lc1 in S401 described above and the slip rate λ is equal to or smaller than the second threshold value Lc2 larger than the first threshold value Lc1 in S403, that is, the slip rate λ is In a relatively small region, the process proceeds to S404, where the first initial engine required torque TEF obtained by filtering the engine torque Teg is set as the second control amount TTCS2. Thus, by setting the first initial engine required torque TEF and starting the feedback control, it is possible to prevent a sudden change in the engine torque Teg and avoid an influence on the vehicle behavior. Further, by using the first initial required engine torque TEF obtained by filtering the engine torque Teg, it is possible to compensate for a time delay until the engine torque Teg converges to a desired value and improve the response.

  If the slip ratio λ exceeds the second threshold value Lc2 in S403 described above, that is, if the slip ratio λ is large, the process proceeds to S405, where the first initial required torque Tii and the running resistance torque Tp are the sum. 2 is set as the second control amount TTCS2. As a result, feedback control is started from the maximum initial torque that can accelerate the vehicle without causing excessive slip of the drive wheels, and the excess slip can be quickly converged without greatly affecting the vehicle behavior. Can do.

  Returning to FIG. 1, the control amount setting unit 4 is provided as a driving force correction unit, and receives the first control amount TTCS1 from the first traction control unit 2 and receives the first control amount TTCS1 from the second traction control unit 3. A control amount TTCS2 of 2 is input. Then, the first control amount TTCS1 and the second control amount TTCS2 are compared, and the smaller one (the one with the larger torque reduction amount) is set as the control amount TTCS by the driving force control device 1, and the engine Output to the control unit 5. When the control amount TTCS signal is input from the driving force control device 1, the engine control unit 5 executes control so as to limit the driving force to the control amount TTCS or less.

  That is, as shown in FIG. 2, the driving force control program in the above-described driving force control device 1 first calculates the first control amount TTCS1 in S101, and the first traction control unit 2 calculates the first control amount in S102. The second traction control unit 3 calculates a second control amount TTCS2.

  Then, the process proceeds to S103, where the first control amount TTCS1 and the second control amount TTCS2 are compared. If the first control amount TTCS1 is equal to or smaller than the second control amount TTCS2, the process proceeds to S104, where When the control amount TTCS1 is set as the control amount TTCS and the first control amount TTCS1 is larger than the second control amount TTCS2, the process proceeds to S105, and the second control amount TTCS2 is set as the control amount TTCS.

  Thereafter, the process proceeds to S106, and the control amount TTCS set in S104 or S105 is output to the engine control unit 5 to exit the program.

  As described above, according to the present embodiment, the first traction control unit that estimates the frictional circle limit of the road surface and calculates the control amount of the driving force to reduce the torque based on the frictional circle limit as the first control amount TTCS1. 2 and a second traction control unit 3 that calculates a control amount of the driving force for torque reduction based on at least the slip ratio of the wheel as a second control amount TTCS2, and the control amount setting unit 4 has the first control. The amount TTCS1 and the second control amount TTCS2 are compared, and the smaller one (the one with the larger torque reduction amount) is set as the control amount TTCS by the driving force control device 1 and output to the engine control unit 5 It is configured.

  For this reason, it is difficult to estimate the friction coefficient μ between the tire and the road surface, such as when going straight ahead or at the time of starting, and driving that does not require much lateral grip of the tire from the viewpoint of vehicle stability. Under the conditions, the grip in the tire driving direction can be used up sufficiently by the second traction control unit 3 that detects the slip ratio of the tire and limits the driving torque. Also, under driving conditions where the friction coefficient μ between the tire and the road surface can be estimated with high accuracy by cornering or the like, tire slip is prevented in advance by feedforward control of the driving torque by the first traction control unit 2, and Keeping the direction grip high can improve vehicle stability. Then, when shifting from cornering or the like to cornering or the like, or when shifting from cornering or the like to the time of straight traveling or starting, the larger torque reduction amount is set as the control amount. Therefore, since the control amount smoothly shifts without sudden change, more natural feeling control can be achieved.

Functional block diagram showing the configuration of the driving force control device Driving force control program flowchart Functional block diagram showing the configuration of the first traction control unit Flow chart of first control amount calculation program Flow chart continuing from FIG. Explanatory drawing showing an example of engine torque set by engine speed and throttle opening Explanatory drawing which shows an example of the relationship between the accelerator opening and throttle opening for generating required engine torque Flow chart of additional yaw moment calculation routine Illustration of lateral acceleration saturation coefficient Characteristic map of vehicle speed sensitive gain Explanatory diagram of the difference in the value of the additional yaw moment on the high and low μ roads Illustration of over-tyre force to be suppressed Functional block diagram showing the configuration of the second traction control unit Flowchart of second control amount calculation program

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Driving force control apparatus 2 1st traction control part (1st control amount calculating means)
2a Engine torque calculation unit 2b Required engine torque calculation unit 2c Transmission output torque calculation unit 2d Total driving force calculation unit 2e Front / rear ground load calculation unit 2f Left wheel load ratio calculation unit 2g Each wheel ground load calculation unit 2h Each wheel front / rear force calculation unit 2i Each wheel required lateral force calculation unit 2j Each wheel lateral force calculation unit 2k Each wheel friction circle limit value calculation unit (friction circle limit value setting unit)
2l Each wheel required tire resultant force calculation unit (first tire force estimation unit)
2m Each wheel tire resultant force calculation part (second tire force estimation part)
2n Each wheel required overtire resultant force calculation unit (first overtire force estimation unit)
2o Each wheel over tire resultant force calculation part (second over tire force estimation part)
2p over-tyre force calculation unit (first control amount setting unit)
2q overtorque calculation unit (first control amount setting unit)
2r First control amount calculation unit (first control amount setting unit)
3 Second traction control unit (second control amount calculation means)
3a Vehicle speed calculation unit 3b Slip rate calculation unit 3c Total grip force calculation unit 3d Engine torque calculation unit 3e Travel resistance torque calculation unit 3f Second control amount calculation unit 4 Control amount setting unit (driving force correction means)
5 Engine control unit

Claims (4)

A first control amount calculating means for estimating a friction circle limit of the road surface and calculating a control amount of a driving force for torque reduction based on the friction circle limit as a first control amount;
A second control amount calculation means for calculating a control amount of the driving force for torque reduction based on at least the slip ratio of the wheel as a second control amount;
Driving force correction means for correcting the driving force in accordance with the first control amount and the second control amount;
The equipped Rutotomoni,
The first control amount calculation means includes:
A first tire force estimating unit that estimates a tire force generated on a wheel based on a driver request as a first tire force;
A second tire force estimating unit that estimates the tire force currently generated on the wheel as the second tire force;
A friction circle limit value setting unit for setting a friction circle limit value of the tire force;
A first over-tyre force estimation unit that estimates a tire force that exceeds the friction circle limit value as a first over-tire force based on the first tire force and the friction circle limit value;
A second over-tyre force estimating unit for estimating a tire force exceeding the friction circle limit value as a second over-tyre force based on the second tire force and the friction circle limit value;
A first control amount setting unit that sets the first control amount based on the first overtire force and the second overtire force;
Driving force control apparatus for a vehicle characterized by comprising a. 2. The driving force correction means compares the first control amount and the second control amount, and limits the driving force so as to be less than a smaller control amount. Vehicle driving force control device. The first control amount calculation means includes a difference with respect to the friction circle limit due to a resultant force of a lateral force generated on the wheel and a currently generated longitudinal force based on a driver request, and a lateral force currently generated on the wheel. When the longitudinal force and the resultant force due to the driving force control apparatus for a vehicle according to claim 1 Symbol mounting, characterized in that calculating the first control amount on the basis of either one of difference with respect to the friction circle limit of. The first control amount calculation means includes a difference between a longitudinal force in which the resultant force with the lateral force generated on the wheel based on the driver request matches the friction circle limit and the currently generated longitudinal force, The first control amount is calculated based on any one of a difference between a longitudinal force in which a resultant force with a generated lateral force coincides with the frictional circle limit and a currently generated longitudinal force. The vehicle driving force control apparatus according to claim 1.

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